JPH0441646B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blow-molded plastic hollow body for attaching other members such as table legs to a table top plate made of a blow-molded plastic hollow body. Regarding separate member attachment structure.

[Prior Art] With an insert placed in a blow molding mold, a plastic parison is expanded, and a separate member is added to a blow molded plastic hollow body in which the insert is integrally joined to the blow molded plastic wall. For example, the means for attaching the
The one described in Publication No. 151014 is known.

[Problems to be Solved by the Invention] Conventionally, in a configuration in which table legs are attached to a table top made of a hollow blow-molded plastic body, for example, the legs are attached to attachment portions formed in the hollow body. However, blow-molded plastic hollow bodies are partially deformed due to shrinkage distortion caused by cooling after molding, so there is considerable damage to the leg attachment parts of the top plate. This will not only cause errors and hinder the leg installation work, but also cause problems such as distortion of the mounting part, which will cause the strength of that part to decrease over time, leading to cracks, gaps, and deformation. It was hot.

[Means for Solving the Problems] The present invention aims to solve the above-mentioned problems, and in order to achieve the purpose, it is configured as follows.

That is, in a separate member mounting structure in which a hard mounting bracket is buried as an insert during blow molding in a blow-molded plastic hollow body, and another member is attached to the mounting bracket with bolts, the mounting bracket is a plate-shaped member. and a plurality of protrusions integral therewith, with holes formed inside the plurality of protrusions in the axial direction and a bulge formed on the outside of the protrusions, and the plate-shaped body of the mounting bracket is hollowed out. A blow that is located on the wall surface of the body, and is embedded so that the entire plurality of protrusions including the bulges protrude from the wall surface of the hollow body into the hollow part, and are wrapped in a support wall extending from the wall of the hollow body to the hollow part. It has a structure in which separate parts are attached to a molded plastic hollow body.

[Function] According to the present invention, the hard mounting bracket has a plate-like body and a plurality of protrusions integral with the plate-like body, and has holes formed inside the plurality of protrusions in the axial direction thereof, and expands outward from the protrusions. The mounting bracket has a plate-shaped body positioned on the wall surface of the hollow body, and the entire plurality of protrusions including the bulges are made to protrude from the wall surface of the hollow body into the hollow portion. Since the mounting bracket is inserted into the support wall extending from the wall of the hollow body to the hollow part, even if the hollow body is partially deformed after blow molding, the mounting bracket will remain intact. There is no error at all in the mounting positional relationship between the parts and other members. Therefore, another member can be easily attached to the mounting bracket. Furthermore, since the mounting position of the separate member relative to the mounting bracket is uniform throughout, the bolt pull-out strength and rotational torque strength are improved as a whole, and cracks, gaps, and deformations do not occur in the mounting portion of the separate member.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

Figures 1 to 3 show the blow-molded plastic hollow body according to the present invention used as a table top, and Figures 4 to 6 show the blow molding process for the top plate. .

10 is the top plate of the table, made of polyethylene,
It has a hollow double-walled structure by blow molding thermoplastics such as polypropylene, ABS resin, and polycarbonate.

30 is a leg of the table; 31 is a flange extending from one end of this leg 30;
is attached to the top plate 10 by bolts 32 of a mounting bracket 20 which is an insert. 11 and 12 are plastic upper and lower walls,
13 is a hollow portion formed between the upper wall 11 and the lower wall 12. The mounting bracket 20 is made of metal or hard plastic, and consists of a plate-like body 21 and four protrusions 25 that protrude from the plate-like body 21 into the top plate 10. A bulging portion 26 is formed, and a hole 22 passing through in the axial direction is formed inside the protrusion 25, and a female thread is formed in the hole 22. The outer peripheral edge 23 of the plate-shaped body 21 is buried near the surface of the lower wall 12, wrapped in the proximal wall 14a of the support wall 14 extending inward from the plastic lower wall 12, and is embedded in the first fitting. It constitutes joint A.

Further, the expanded portion 26 of the protrusion 25 that integrally projects from the plate-shaped body 21 is also wrapped by the upper end wall 14b of the support wall 14 extending inward from the lower wall 12 and buried inside the top plate 10, and is buried inside the top plate 10. It constitutes a fitting part B.
Mounting bracket 20 and plastic bottom wall 12
are welded together during blow molding, and
The support wall 14 extending from the lower wall 12 and the upper wall 11 opposing it are also welded together during blow molding.

Furthermore, the plate-shaped body 21 of the mounting bracket 20 is attached to the lower wall 1.
A recess 15 in which the position of the flange 31 of the leg portion 30 is regulated by being located slightly inward from the surface of the recess 15
is formed. When attaching the leg portion 30, the leg portion 30 is attached to the top plate 10 by positioning the flange 31 in the recess 15 and screwing the bolt 32 into the female thread of the protrusion 25.

Next, the blow molding process of the top plate 10 will be explained with reference to FIGS. 4 to 6.

41 and 42 are cavities, and 45 is an insert member that connects the mounting bracket 20 to the cavity 44.
This is a holding part for temporary fixing inside the mounting bracket 20, and a convex part 46 of the holding part 45 is inserted into the hole 22 of the mounting bracket 20.

After the mounting bracket 20 is placed in the cavity 44 as described above, a thermoplastic plastic such as polyethylene is melt-kneaded in an extruder (not shown) and the extruded parison P is shown in FIG. It is placed between the split molds 41 and 42 as shown in FIG.

Next, pre-blow Parison P and mold 4.
1 and 42, a part of the parison P is welded between one cavity 43 and the mounting bracket 20, and the opposing parison P is welded together, as shown in FIG. Located around the mounting bracket 20.

Next, as the molds 41 and 42 are further closed, the parison P between the cavity 43 and the mounting bracket 20 is compressed, so pressurized fluid is introduced into the parison P as shown in FIG. Expand P along the shapes of cavities 43, 44 and mounting bracket 20. At this time, the parison P is welded together so as to wrap around the bulging portion 26 and the outer peripheral edge portion 23 of the mounting bracket 20, thereby forming the upper wall 11, the lower wall 12, and the support wall 14 of the top plate 10.

Next, after cooling the molded product, the molds 41 and 42 are opened and the cooled molded product is taken out, thereby obtaining the top plate 10 as shown in FIG. 1. This top plate 10
Attach the mounting bracket 20 as shown in Figure 3.
and the plastic lower wall 12 are welded together during blow molding, and the support wall 14 extending from the lower wall 12 and the upper wall 11 opposing thereto are also welded together during blow molding.

[Effect of the invention] According to the present invention, the following effects can be obtained.

In other words, a hard mounting bracket has a plate-like body and a plurality of protrusions integrated therewith, and has holes formed inside the plurality of protrusions in the axial direction thereof, and a bulge formed on the outside of the protrusions. The above-mentioned mounting bracket has its plate-like body positioned on the wall surface of the hollow body, and the plurality of protrusions including the bulges are all protruded from the wall surface of the hollow body into the hollow part, so that the mounting bracket is attached to the wall of the hollow body. Since the resin is embedded so as to be wrapped in the support wall extending into the hollow part, even if the mounting bracket is inserted during blow molding of the hollow body, the resin can easily be wrapped around the mounting bracket, and no molding defects will occur.

Also, the mounting bracket is hard,
It has a plate-like body and multiple protrusions, and holes are formed in the axial direction of the multiple protrusions, and a bulge is formed at the tip, so that the formed hollow body shrinks and deforms after blow molding. Even if the mounting bracket is attached to another member, no error occurs in the mounting positional relationship between the mounting bracket and the other member, and the other member can be easily attached to the mounting bracket. Also, since the mounting position of the mounting bracket relative to other components is uniform throughout,
The pull-out strength and rotational torque strength of the bolt are improved as a whole, and cracks, gaps, and deformation do not occur in the attachment portion of another member, and the fixing strength can be excellent.

[Brief explanation of the drawing]

Fig. 1 is a bottom view of the top plate of a table which is a blow-molded hollow body according to the present invention, Fig. 2 is a partially enlarged view of the same as above, Fig. 3 is a sectional view taken along line I-I of Fig. 2, and Fig. 4 Figure 6 is a sectional view of the main part of the mold showing the blow molding process of the top plate. 10...Top plate, 11...Upper wall, 12...Lower wall,
13... Hollow part, 14... Support wall, 20... Mounting bracket, 21... Plate-shaped body, 22... Hole, 23
...Outer peripheral edge, 25...Protrusion, 26...Bulging part,
30...leg, 31...flange, 32...bolt.

Claims (1)

[Claims] 1. In a separate member mounting structure in which a hard mounting bracket is buried as an insert during blow molding in a blow-molded plastic hollow body, and another member is attached to the mounting bracket with bolts, the above-mentioned mounting bracket is attached to a plate-shaped member and It has a plurality of protrusions integral with the mounting bracket, and has holes formed inside the plurality of protrusions in the axial direction and a bulge formed on the outside of the protrusions, and the plate-like body of the mounting bracket is a hollow body. The plurality of protrusions, including the protrusions, are located on the wall surface, and are embedded so that the entire plurality of protrusions, including the bulges, protrude from the wall surface of the hollow body into the hollow part, and are surrounded by a support wall extending from the wall of the hollow body to the hollow part. Features a structure for attaching separate parts to a blow-molded plastic hollow body.